Conventionally, there is a known pool gate provided in a canal unit, which is provided between pools constructed inside a nuclear reactor building in a nuclear power generating station or inside a building adjacent to the nuclear reactor building, such that both pools are partitioned by the pool gate (for example, see Patent Literature 1). This pool gate has a U-shaped packing that is in contact with the wall surface of the pool on the canal unit side or in contact with a slot and receives the lateral direction load due to water pressure. At this time, the packing, which is an elastic packing, is pressurized and is thus brought into close contact with the wall surface on the canal unit side or contact with the slot, whereby exhibiting the sealing function.